Refrigeration



Feb. 28, 1933. G. E. HULSE 1,899,036

REFRIGERATION Filed Dec. 5, 1930 zsheets-sheet J INVENTOR BY i; 74%

}d\ ATTORNEYS Feb. 28, 1933. G, HULSE 1,899,036

REFRIGERATION Filed Dec. 3, 1930 2 Sheets-Sheet 2 INVENTOR A TTORNE x;

Patented Feb. 28, 1933 UNITED, STATES PATENT" OFFICE v \M V I G EORGE E.HULSE, OF NEW HAVEN, CONNECTICUT, ASSIGNOB TO THE SAFETY CAB HEATING &LIGHTING COMPANY, A CORPORATION OF NEW JERSEY REFRIGERATION Applicationfiled December 8, 1930. Serial No. 499,669.

This invention relates to refrigeration.

One of the objects of this invention is to provide a refrigerationsystem which will be highly efiicient in operation while reliably copingwith certain variable conditions met with in practice. Another object ofthis invention is to provide a system of the above character which willbe of thoroughly simple and practical arrangement and of dependable andlasting action. Another object is to provide a device of the abovecharacter which, because of such features as thorough simplicity of itsworking parts, will require a minimum amount of attention and may beoperated by unskilled attendants. object is to provide a system of theabove character which will be economical in use. Other objects will bein part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possibleembodiments of my invention,

Figure 1 is a transverse cross sectional view of a railway refrigeratorcar showing certain parts of my apparatus and system in end elevation,

Figure 2 is a central cross sectional view of a valve used in my system,

Figure 3 is a front elevation of a valve,

partially in cross section, employed in my Another of heat-resistantmaterial to form a compartment 12. The exterior walls 13 of car 10 arealso constructed in any suitable manner to be of low heat conductivity.Thus compartment 12 is well insulated from the temperaglne 17 is housedtherein. Thus the heat ensuing from the operation of this engine isexcluded from compartments 12 and 14. This engine may be of any desiredconstruction although it has been found preferable to employ asmallDiesel engine adapted to run continuously for substantial periodsof time. Engine 17 may be cooled in any suitable way; for example, anopening 18, leading to the exterior of the car, is disposed adjacent afly wheel 19 of the engine and another opening 20 is positioned in theupper portion of the compartment. A fan 21 secured to or built into flywheel 19 draws air in through opening 18 and forces it out throughopening 20 after passage over the engine. This circulation of air coolsthe engine to an eflicient working temperature, and also decreases thepossibility of suflicient heat being retained in compartment 15 to causeleakage through walls 16 into compartments 12 and 14.

Crankshaft 22 of engine 17 extends through wall 16 to drive a shaft 23from which, by way of suitable gearing 30, is driven a compressor 24.Compressor 24 is preferably of the rotary type and provided with aninlet pipe 25 and an outlet pipe 26.

Outlet pipe 26 leads to the top 27 of a plurality of tubes 28 whichformany suitable efiicient air-cooled condenser. Condenser 28 is adaptedto receive a compressedgaseous refrigerant, such as sulphur dioxide,from compressor 24, through outlet pipe 26 and to reduce it intemperature, thereby condensing and changing it to liquid form. As ismore clearly shown in Figure 4, condenser 28 is positioned adjacent anopening 31 leading to the exterior of the car 10. This opening isrovided with a sheet metal grating generaly indicated at 32, thuspermitting outside air to enter and ass over condenser 30.

A cond it 33, or example of sheet metal, has its up portion fitted aboutopening 31 and exten car 10 to enclose condenser 28, com ressor 24, andthe various working parts t ereof. An open 34 extends through the floorof car 10, an the o posite end of conduit 33 is terminated at t isopening. By this construction air entering through opening 31 flows downover condenser 30 and compressor 24 to exit through opening 34.

To insure this movement, a fan :35 is mounted on a shaft 51 connected todriving shaft 23 by a coupling 36 and rotatably hel in place b astandard 37. -This fan, when actuated, orces air inwardly throughopening 31, causing the above described movement of air to take place,extracting heat from the condenser 28 and compressor 24 within conduit33, the heated air passing out through opening 34.

The li uefied refrigerant is passed by a pipe 38 Figure 4) to a receiver39 to be stored for later refrigerating purposes. A reservoir 40 at thetop of the car in the drawings is insulated by walls 41 fromcompartments 12 and 14 and holds a substantial quantity of liquid, suchas brine, to be circulated in space 14 and absorb heat therefrom bymeans to be described hereinafter. Disposed within reservoir 40 is anexpansion coil 42 connected to receiver 39 by pipe 43 in which isinserted an expansion valve 44 controlled by the pressure in evaporatorcoil 42. After expansion and evaporation in coil 42, the refrigerantleaves coil 42 by a pipe .46, but under the control of a thermostaticvalve 45, and .then passes to the'inlet pipe 25 of compressor 24. Valve45 is thermostatically controlled in accordance with the temperature ofthe contents of reservoir 40 and, as is now clear, is on the suctionside of compressor 24. When the brine in tank 40 has been suficientlycooled, valve 45 closes, stopping the cycle of steps through which therefrigerant passes to achieve refrigeration. Upon increase intemperature of the brine, valve 45 opens, whence evaporation ofliquefied refrigerant in coil 42 may proceed and the cycleis resumed.'Valve 44 thus allows liquefied refrigerant, under pressure in receiver39 and condenser 28, to expand into expansion coil 42 .where itevaporates to maintain at relatively fixed'low temperature under controlof valve 45, the contents of reservoir 40, and is then led back to thecompressor 24 to repeat the refrigeration cycle.

A pipe 47 leads from the bottom of reservoir 40 and is connected to aseries of ipes generally indicated at 48 in space 14. ad-

downwardly toward the floor of ing from the other end of Dines 48 is apipe 49 extending through partition 11 to enter compartment 12. v

. Anchored to the floor of car 10 is a rotary pump 50, driven b shaft51, which is connected to driving s aft 23. The inlet 52 of pump isconnected to pipe 49 and the outlet 53 is connected to a 1 54 leading tothe top of reservoir 40. ii en pump 50 is actuated by shaft 51, acirculation of the brine takes place through pipes 48, reservoir 40 andconnected parts, as indicated b the arrows in the drawings. Thus therine, cooled by coil 42, leaves reservoir 40, passes through pipes 48,extracting heat from chamber 14, and, warmed, enters pipe 49 to pump 50and leaves pump 50 to re-enter reservoir 40 by pipe 54, to be cooledagain by coil 42.

Inlet pipe 49 of pump 50 and outlet pipe 54 are connected by pipe 55 andpipe 56 respectively, to form a bypass generally indicated at 82, andinterposed between pipes 55 and 56 is a thermostatic valve 57 whoseconstruction is to be described hereinafter. A thermostatic bulb 58 isdisposed in space 14 and is connected by pipe 59 to valve 57 to make thelatter responsive, in a manner to be hereinafter more clearly described,to the temperature of space 14. Likewise, a ther mostatic bulb 60 isdisposed in reservoir 40 and is connected to thermostatic valve 45 by apipe 61 to make the valve 45 responsive to the temperature of the mediumcontained in this reservoir.

Referring now more particularly to Figure 2, a possible construction ofthermostatic valve 45 is shown in detail. A bellows 62 is anchored as at63 to a casing 64. Pipe 61 leading from thermostatic bulb 60 is threadedinto an inlet '65 in this casing to be connected directly to bellows 62.A casin 66 is secured to annular flanges 67 exten ing from casing 64 byany desired means, such as'screws 68. A partition 69 separates theinterior of casing 64 from the interior of casing 66. Casin 66 isdivided into two chamber portions 71 and 73 by a valve seat 70, portion71 being connected at port 72 to pipe 46 leading from coil 42, andportion 73 eing connected at port 7 3 to pipe 46 leading to compressor24. Thus-the evaporated refrigerant, in passing from evaporator .42 tocompressor 24, must pass through valve opening 75 in the seat 70. a

A rod 76, secured to the unanchored end of bellows 62, extends through asuitable stufling box in wall 69 and has connected at its opposite end avalve 77 coacting with and controlling valve opening 75. Bulb 60,submerged in the brine in reservoir 40, contains a suitable volatileliquid sensitive to temperature changes. When an increase in temperatureof the brine, and hence of the volatile liquid in bulb 60, takes place,the vapor pressure increases and the resultant increase in ressure inthe bellows 63 causes the unanc ored end of the bellows to force shaft76 to the left, as viewed in Figure 2, to open valve 77 and thus permitthe passage of evaporated refrigerant from coil 42 to condenser 24.Reduction in temperature of the brine to the desired value causes areverse action and the closure of valve 75-7 7.

Referring now to Figure 3, there is shown a possible construction forvalve 57. Preferably it is substantially similar in construction tovalve 45 of Figure 2. A port 78 of the valve is connected to pipe 56 ofthe bypass v 82, and the other port 79 is connected to pipe 55 of bypass82. A valve head 80, coacting with valve 0 ning 81, is controlled by athermostatic ellows 83 connected to thermostatic bulb 58 (Figures land4) by pipe 59, bulb 58 containing a suitable volatlle liquid whoseaction, in response to the temperature in space 14, will now be clear inview of the above described control of valve 45.

Considering now the action of my refrigeration system, let it be assumedthat the refrigerating car is in transit and is loaded with perishablegoods whichshould be maintained between certain definite temperaturelimits for most efficient carriage and storage. Reservoir 40, pipes 48,and associated pipe connections are filled with brine of suitablecomposition, and engine 17, which, as above noted, is adapted to runcontinuously for substantial periods of time, is in operation.Furthermore, let it be assumed that the car has just been loaded and theenglne 17 ust started; therefore the temperature 1n space 14 is abovethat preferred and the temperature of the brine in reservoir 40 is abovethat preferred for proper refrigerating purposes. This brine should bemaintained at a temperature substantially below, that of the temperatureat which space 14 is to be maintained. For example, if space 14 1n thecar is tobe maintained at 40 F., it may be desirable to maintain thebrine at a temperature of 35 F.'

As the engine 17 is running at its normal speed of operation, compressor24, which is connected directly thereto, compresses the gaseousrefrigerant and forces it through outlet pipe 24. The compressed gaseousrefrigerant enters condenser 28 to be cooled, condensed, and thusliquefied. Fan 35 is running. Thus a constant flow of air is moving downover condenser 28, compressor 24 and out through opening 34. Thiscombined compressin and cooling eflect liquefies the gaseous re rigerantand the refrigerant is then conducted to receiver 39 by pipe 38.

As the temperature of the brine in the reservoir 40 has been assumed tobe above 35, the substance contained in thermostatic bulb is at a vaporpressure sufiicient to actuate valve 45, the pressure causing theunanchored end of bellows 62 to move valve head away from its seat 70,thus allowing free passage of evaporated refrigerant from evaporator 42through the valve to the compressor 24. As the action of the condenserand compressor continues, liquefied refrigerant flows from receiver 39,through pipe 43, under control of expansion valve 44, to expansion coil42. The liquefied refrigerant evaporates in coils 42 to absorb heat fromthe brine contained in reservoir 40. The evaporated refrigerant returnsto compressor 24 by pipe 46 (valve 45 being open) connected to inletpipe 25 to repeat the refrigeration cycle. This action continues untilthe brine is cooled to the desired temperature, above assumed to be 35,whenthe vapor pressure in thermostatic bulb 60 becomes reduced to causebellows 62 to contract and reseeit valve head 75, thus closing valve 45and stopping the flow .of gaseous refrigerant to compressor 24.

Cooling of the brine ceases for no expansion is taking place in coil 42until the temperature of the brine rises above 35, when this action isrepeated.

Simultaneously with the above described action, rotary pump 50 is beingactuated by driving shaft 51 to circulate the brine through thecirculating path which includes pipes 48 in space 14. The cooled brineleaves the bottom of reservoir 40 through pipe 47 to enter pipes 48 andextract heat from space 14. After exerting this cooling effect on space14, the warmed brine travels through pipe 49, to pump 50 and throughpipe 54 back to thetop of reservoir 40 where it is cooled by the actionof expansion coil 42. During this action, valve 57 is closed. Thiscirculation of brine continues until the tempera ture in space 14reaches that preferred, above assumed to be 40 F., when the vaporpressure in thermostatic bulb 58 is reduced to cause bellows 57 tocontract, unseating valve head from its seat 81, and thus opening valve57. Bypass 82 is thus made effective as a shunt. The opening of valve 57forces the brine to flow from outlet 53 of pump 50 through pipe 56,valve 57 and pipe '55 and back to the inlet of the pump. Bypass 82 isthereby established and pump 50 has no effect on the brine in reservoir40 or in pipes 48. Circulation of the brine in space 14 ceases until thetemperature of this space rises above 40 when the valve 57 closes,bypass 82 is made ineffective, and the circulation. of brine through itsheat-abstracting path is resumed.

The compressor 24 is being driven continuously so that the brine may bemaintained at an even temperature subject to the control of thermostaticvalve 45. Thus any rise in the temperature ofthe brine in reservoir 40due, for example, to the return thereto of warmed brine from pipes 48,opens valve 45 to cause refrigeration to take place in reservoir 40. Thelatter may, and preferably does, have a substantial capacity so as toHold, for circulation as needed, a substantial quantity of brine, thelatter'being cooled, by coil 42, as and when cooling thereof is needed.In this manner a practical method for maintaining the goods in space 14at a substantially constant temperature is assured.

It will thus be seen that by this thoroughly simple and practicalconstruction and paratus I have provided a refrigeration system welladapted towithstand the hard wear and tear of operation on vehicles suchas railroad cars. By employing a brine circulating system operatingindependently of the other parts of my refrigerator system, I am able tomaintain the refrigerated space of the vehicle at a temperature whosevariations will be slight and inconsiderable. Thus, the perishable goodsto be stored will be free from damage due to a quick rise oftemperature. The extreme simplicity of the action of the working partsis desirable in that it reduces to a minimum the possibility of abreakdown, and also permits the o eration of this apparatus by carelessan unskilled attendants. These and many other important advantages andthe objects above noted will thus be seen to be successfully achieved.

As many possible embodiments may be made of the above invention and asmany changes may be made in the embodiment above set forth, it is to beunderstood that all matter hereinabove set forth, or shown in theaccompanying drawings is to be interpreted as illustrative, and not in alimiting sense.

I claim:

1. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, means for circulating a fluidmedium in said space, a reservoir for storing said fluid medium, arefrigeration unit employing a gaseous refrigerant and having anexpansion member disposed in said reservoir in thermal contact with saidfluid medium, an internal combustion engine adapted to run continuouslyfor substantial periods of time for driving the compressor of said unit,a valve for controlling the flow of said refrigerant to said expansionmember, thermostatic means responsive to the temperature of said fluidmedium for controlling said valve, a pump for forcing said fluid mediumthrough said circulating means, a bypass associated with saidcirculating means, a valve for regulating the efl'ectivity of saidbypass, and thermostatic means responsive to the temperature in saidspace for controlling said valve.

2. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a containing means for storing afluid medium, means for circulating said fluid medium in said space, arefrigeration unit having an expansion member disposed in thermalcontact with said fluid medium, an internal combustion engine adapted torun continuously for substantial periods of time for driving thecompressor of said unit, means for controlling the supply of refrigerantto said expansion member, means responsive to the temperature of saidfluid medium for controlling said last mentioned means, a pump forforcing said brine through said circulating means, a by-pass associatedwith said circulating means, means for controlling the effectivity ofsaid by-pass, and thermostatic means responsive to the temperature insaid space for controlling said last mentioned means.

3. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a reservoir for storing brine, acirculating system for said brine in said space, a refrigeration unithaving an evaporator member for cooling said brine in accordance withthe rate of evaporation taking place therein, an internal combustionengine adapted to run continuously for substantial periods of time todrive the compressor of said unit, means for controlling the rate ofevaporation in said evaporator member, means responsive to thetemperature of said brine for controlling said last mentioned means,means in said circulating system for causing circulation of brine totake place therein, a bypass associated with said circulating system,means for controlling the effectivity of said by-pass, and meansresponsive to the temperature in said space for controlling said lastmentioned means.

4. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit employing agaseous refrigerant, an expansion member of said unit thermally relatedto a fluid and adapted to extract heat therefrom according to the rateof expansion of said refrigerant taking place therein, means responsiveto the temperature of said fluid for regulating said rate of expansion,means for circulating said fluid in said space adapted to bring saidfluid into thermal relation to said space to extract heat therefrom, asecond circulating means for circulating said fluid substantially out ofthermal relation with said space, means for causing said medium to flowthrough either of said last mentioned means, and temperature-responsivemeans in. said space for controlling the action of said last mentionedmeans.

5. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit, theexpansion member of said unit thermally related to a fluid and adaptedto extract heat therefrom according to the rate of expansion takingplace therein, means responsive to the temperature of said fluid forregulating said rate of expansion, circulating means for said means forcirculating said fluid substantially out of thermal contact with saidspace, temperature-responsive means in said space for selectivelydisposing said fluid in either of said circulating means.

6. In a refrigeration system, in combination, means forming a spacewhose temperature is to beregulated, a refrigeration unit, an expansionmember of said unit disposed in thermal contact with a fluid and adaptedtoe'x'tract heat therefrom according to the rate of expansion takingplace therein, means responsive to the temperature of said medium forregulating said rate of expansion, circulating means for said fluid insaid space adapted. tohring said fluid in thermal contact with saidspace to extract heat therefrom, a second circulating means for saidfluid substantially out of thermal contact with said space, means forforcing said fluid through either of said systems, thermostatic means insaid space for selectively disposing said medium in either of said twocirculating means.

7. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit, motive meansfor said refrigeration unit, an expansion member of said unit disposedin thermal contact with a fluid and adapted to extract heat therefromaccording to the rate of expansion taking place therein, meansresponsive to the temperature of said medium for regulating said rate ofexpansion, a circulating means for said fluid adapted to bring saidfluid in contact with said space to extract heat therefrom, a secondcirculating means for circulating said fluid substantially out ofthermal contact with said space, means for causing said medium to flowthrough either of said two circulating means, and temperature-responsivemeans in said space for regulating the action of said lastmentionedmeans.

8. In a refrigeration system, in combination, means forming a spaceWhose temperature is to be regulated, a refrigeration unit, motive meansfor said refrigeration unit, an expansion member of said unit disposedin thermal contact with a fluid adapted to extract heat therefromaccording to the rate of expansion taking place in said member, meansresponsive to the temperature of said medium for controlling said rateof expansion in said expansion member, a circulating system for saidfluid adapted to bring said fiuid into thermal contact with said spaceto extract heat therefrom, a second system for circulating said fluidsubstantially out of thermal contact with said space, a pump for forcingsaid fluid through either of said circulating means, and thermostaticmeans in said space for selectively disposing said me-' dium in eitherof said systems.

9. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit, an internalcombustion engine adapted to run continuously for substantial periods oftime to drive an element of said unit, an expansion member in said unitdisposed in thermal contact with a fluid adapted to extract heattherefrom according to the rate of expansion taking place therein, meansresponsive to the temperature of said medium for controlling said rateof expansion, circulating means for said fluid adapted to bring saidfluid into thermal contact with said space to extract heat therefrom, asecond circulating means for disposing said fluid substantially out ofthermal contact with said space, temperature-responsive means in saidspace for selectively disposing said fluid in either of said circulatingmeans.

10. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit for cooling afluid medium, circulating means for said fluid adapted to bring saidfluid into thermal relation with said space to extract heat therefrom, asecond system for circulating said fluid substantially out of thermalcontact with said space, and means responsive to the temperature in saidspace for selectively disposing said fluid in either of said twocirculating means.

11. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unitv adapted tocool a fluid upon actuation, motive means for driving an element of saidun t, circulating. means for said fluid adapted to bring said fluid intothermal contact with said space to extract heat therefrom, a secondcirculating means for said fluid substantially out of thermal contactwith said space, and means responsive to the temperature in said spacefor selectively disposing said fluid in either of said two circulatingmeans.

12. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit adapted tocool a fluid upon actuation, motive ineans for driving an element ofsaid unit, a circulating system for said fluid adapted to bring saidfluid in contact with said space to extract heat therefrom, a secondcirculating means for said fluid substantially out of thermal contactwith said space, means for forcing said medium through either of saidsystems, and means responsive to thetemperature of said space fordisposing'said fluid in said first mentioned circulating means when thetemperature therein is above a certain predetermined value and fordisposing said means said fluid in said second circulating means whenthe temperature of said space is at or below said temperature.

13. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a refrigeration unit adapted tocool a fluid, an internal combustion engine adapted to run continuouslyfor substantial periods of time for driving a driven element of saidunit, circulating means forsaid fluid adapted to bring said fluid intothermal contact with said space to extract heat therefrom, a secondcirculating means for said fluid substantially out of thermal contactwith said s ace, means for forcing said medium throug either of saidcirculatmeans, and means for selectively determining throu h which ofsaid two circulating uid is to be forced according to the temperature ofsaid space.

14. In a refrigeration system, in combination, a space on a vehicle awhole or a part of whose interior temperature is to be regulated, areservoir for storin brine, a refrigeration unit, an internal com ustionengine adapted to run continuously for substantial periods of time todrive the compressor of said refri ration unit, an ex ansion member ofsaid unit disposed in sai reservoir in thermal contact with said brineadapted to extract heat therefrom according to the rate of expansiontaking place therein, a valve for controlling the rate of expansion insaid member, thermostatic means in contact with said brine forcontrolling the action of said valve, a system of conduits connected tosaid reservoir and in thermal contact with said space for circulatingsaid brine therein, a second system of conduits for circulating saidbrine substantially out of thermal contact with said space, a ump drivenb said en 'ne for forcing said brine throng either 0 said systems, a

' valve for selectively disposing said brine in either of said systems,and thermostatic means responsive to the temperature in said a ace forcontrolling said valve to place said uid in said first system when thetemperature therein is above a predetermined valueandto place said fluidin said second system when said temperature is at or below saidtemrature value. I 15.- In a refrigeration system, in combination, meansforming a space whose temperature is to be re lated, means forming acirculating path or a liquid and extending into said space, acontinuously acting pump for forcing said liquid through saidcirculating ath, refrigerating means for cooling the liquid to be passedthrough said path, means connected with said pump and said path adaptedwhen effective to shunt liquid away from said path, and means responsiveto the temperature in said space for controlling said last mentionedmeans.

16. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, means forming a circulating pathfor a liquid and extending into said space, a continuously acting umpfor forcing said liquid through said circulating path, refrigeratingmeans for cooling the liquid to be passed through said ath, meansconnected with said pum an said path adapted when effective to s untliquid away from said path, means responsive to the temperature in saidspace for controlling said last mentioned means, and means responsive tothe temperature of said liquid for controlling the refrigerating actionof said refrigeration means.

17. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, means including pumping means andforming two circulating paths for a refri rant, only one of saidcirculating paths ing thermally related to said space, and means resnsive to the temperature of said space or controllin relativeeffectiveness of said two circu ating paths.

18. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated; a refrigerating apparatusincluding a continuously operated compressor for a refri rant and meansformthe ing a path of flow or refrigerant, said last mentioned meansbeing thermally related to said space; means for bypassing refrigerantfrom said path-forming means; and means responsive to the temperature ofsaid space for controlling the relative conductivity to refrigerant ofsaid path-forming means and said pass means.

19. n a refrigeration system, in combination, means forming a spacewhose temperature is to be lated, means includ' a container and forminga circulating pa through said space for a liquid refrigerant containedtherein, a rotary pump included in said last-mentioned means, aninternal combustion engine for rotating said pump continuously forsubstantial per ods of time, a by-pass for said pump, and valve meansresponsive to the temperature of said space for controlling theeffectiveness of said bypass.

20. In a refrigeration system, in combination, means forming a spacewhose temperature is to be regulated, a container for a refrigerant,means forming a circulating path for said refrigerant between saidcontainer and, said space, refrigerating means for said container, arotary pump in said circulating path, an internal combustion engine fordriving said pump continuously for substantial periods of time, aby-pass for said pump and adapted when open to stop said pump fromcirculating said refrigerant in said circulating path, and valve meansresponsive to the temperature of said space for controlling saidby-pass.

21. In a refrigeration system, in combination, means forming a spaceWhose temperature is to be regulated, containing means for arefrigerating brine, means for circulating said brine between said spaceand said containing means, said means including a rotary pump, arefrigeration unit for said containing means, an internal combustionengine adapted to drive parts of said refrigeration unit and said pumpcontinuously for substantial periods of time, a by-pass for said pumpadapted when open to reduce the effectiveness of said pump, andthermostatic means responsive to the temperature of said space forcontrolling the action of said bypass.

22. In a refrigeration system, in combination, means forming a containerwhose temperature is to be regulated, a refrigeration unit including acompressor and an evaporating member, said evaporating member being inthermal contact with said container, means connecting the intake side ofsaid compressor to the outlet of said evaporating member, a valveincluded in said last-mentioned means, and thermostatic means responsiveto the temperature of the substance being refrigerated' for controllingthe operation of said valve.

In testimony whereof, I have signed my name to this specification this26th day of November, 1930.

- GEORGE E. HULSE.

